The Long Term Evolution (LTE) standard is a standard for wireless communication of high-speed data for mobile devices and data terminals. LTE is based on the GSM/EDGE (Global System for Mobile Communications/Enhanced Data rates for GSM Evolution) and UMTS/HSPA (Universal Mobile Telecommunications System/High Speed Packet Access) network technologies. Relative to GSM/EDGE and UMTS/HSPA, LTE may increase the capacity and speed of the wireless network based on improvements to the radio interface and improvements to the core network.
The LTE standard is based on packet-switched IP networking and does not have inherent support for circuit-switched voice calls. The Voice Over LTE (VoLTE) standard is one approach that may be used to provide voice calls in a network based on LTE.
Presence, as used with respect to network communication, such as voice and messaging communications, may refer to a service that allows a user to be informed about the reachability, availability, and/or willingness to communicate of other users. In communication systems in which presence is enabled, user devices may update a presence server with status information associated with the user of the user device. The status information may include, for example, whether the user is online or not online, or whether the user is idle or busy. Other user devices may receive the status information and may, for example, display the status of a particular user next to a name or other contact information associated with the particular user. The availability of presence information may significantly enhance the utility of communication applications such as instant messaging.